Demand for oil absorbing materials designed for targeted applications is continuously growing due to heavy reliance in developed and developing economies on oil and oil based products. During the production and transport of oil, accidental or intentional spills occur in water or on land, creating numerous environmental and health hazard problems for many years. Even though no single system is likely to be completely effective, the use of oil sorbents is one of the most widely used methods for containing and combating oil spills, especially spills that occur in the sea. The controlling mechanisms of oil sorption by the sorbents could be absorption by a polymer or resin, adsorption at interfaces and in void spaces, capillary action at interfaces and surfaces, or some combination of these. Polypropylene fibers and nonwovens are one of the most commonly used sorbents in oil spill cleanup because of its oleophilic and hydrophobic characteristics.
It is greatly desired that these sorbent materials be produced from non-virgin, recycled materials. For example, processes for producing absorbent articles (e.g., diapers) produces thousands of metric tons of manufacturing waste per year. Not only does this manufacturing waste substantially increase the costs of producing the absorbent articles, but the waste also negatively impacts the environment as it is typically disposed of in landfills and other waste collection areas. In addition to the manufacturing waste generated during their production, many absorbent articles are intended for single use as a disposable product. Thus, the use of such disposable products creates an additional waste stream that is added to those landfills.
Absorbent article waste contains a significant amount of polyolefin (e.g., polypropylene and/or polyethylene) fibers and nonwovens that could be used for oil sorption applications. However, baled article waste and/or article tailings waste is not useful for this application due to its physical form and relatively high percentage of unrecovered active superabsorbent material (SAM) and cellulose materials that create significant challenges for use as oil absorption materials due to their high absorbency of water. Separation of the materials of absorbent article manufacturing wastes and soiled absorbent articles presents a unique challenge due to the various compositions that are difficult and costly to separate into individual components. In particular, absorbent articles can include thermoplastic materials (e.g., polyolefins), cellulosic materials (e.g., pulp fibers), super absorbent materials, adhesives, binders, and other natural and synthetic materials. Soiled absorbent articles present an even greater challenge for recycling due to the presence of various bodily wastes within the article.
Accordingly, there exists a need for a recycling process that provides a useful product generated from manufacturing wastes and/or soiled absorbent articles.